1. Field of the Invention
The present invention relates to a water jet propulsion watercraft, and more specifically, to a water jet propulsion watercraft including a damper section that reduces vibrations transmitted from an engine to a catalytic converter unit.
2. Description of the Related Art
A water jet propulsion watercraft is conventionally provided with a catalytic converter arranged in an exhaust passage. For example, Laid-open Japanese Patent Application Publication 11-11393 discloses a water vehicle having a catalytic converter. The catalytic converter is supported on an intermediate exhaust pipe with a mounting flange. The intermediate exhaust pipe is fixed to a cylinder head of an engine with bolts.
The efficiency with which a catalytic converter treats exhaust gas improves when the exhaust gas is held at a higher temperature as it passes through the catalytic converter. Consequently, it is preferable for the length of an exhaust passage leading from an engine to a catalytic converter to be short. Thus, there are cases in which a catalytic converter unit containing a catalyst is fixed to an engine in order to arrange the catalytic converter closer to the engine.
However, in the case of Laid-open Japanese Patent Application Publication 11-11393, the intermediate exhaust pipe is fixed to a cylinder head of the engine with bolts. Consequently, vibrations of the engine are transmitted directly to the intermediate exhaust pipe and the catalytic converter. As a result, the catalytic converter unit is more likely to experience such troubles as the position of the catalyst shifting out of place and the catalyst becoming damaged. The catalytic converter unit is connected to a water lock. If the water lock is fixed to a hull of the watercraft, then it will be difficult for the water lock and the catalytic converter unit to vibrate in a coordinated manner even if vibrations from the engine cause the catalytic converter unit to vibrate. Consequently, a connecting portion between the water lock and the catalytic converter unit can easily become damaged.